Gray Literature (variant orthography, not exclusively British, "Grey
Literature"), was probably first coined in the last quarter of the 19th
century to designate a manuscript copy or pre-print distributed and
circulated to a select few for peer review of a written work in advance of
and intended for final and formal publication. This is not identical with
a blue-line copy, or galley proof since these are terms used by a publisher
to describe printed materials from signatures prepared for mass production.

The term "grey paper" first appeared in John Ruskin's description of
drawings produced by Joseph William Mallard Turner made on artist's drawing
stock called "grey paper". (See Notes by Mr. Ruskin on his drawings by the
late J. M. W. Turner, R. A. : exhibited at the Fine art society's
galleries, 148 New Bond street, in the spring of 1878 (London : Elzevir
press, 1878): 50) This form of paper was an unbleached stack and was
produced as a wrapping paper and for artist's drawing. Since "gray
literature" originally referred to an author's unfinished work it probably
became an adopted term since it paralleled the artist's sketch that served
as a preliminary idea in various degrees of refinement that preceded and
led to a final production. The term "gray literature" has now taken on a
broader meaning and includes all non-commercially produced literature
inaccessible to the mass market for acquisition since its original target
audience was private rather than open to the public forum.

While I accept Charles Faulhaber's definition of gray literature in
Humanist 17.009 in the terms in which it was given, I wonder if it would
not be helpful to look beyond the immediate institutional classification. I
would suppose that gray literature does not always coincide with that which
is "privately published" -- a volume of poetry, say, produced by
letterpress and given to friends of the poet-printer; a samizdat
publication; a serious work of scholarship put online by the author because
he or she cannot get it published commercially. These things, it seems to
me, differ rather significantly from a research report issued by a
laboratory so that its preliminary work may be distributed to colleagues.
In the former case, the work is the final form; it is the thing itself, not
a preliminary or interim version.

The problem with the institutional definition, as Charles pointed out, lies
in the discrepancy between classification and actual importance. If I am
writing a history of work on DNA, for example, all the interim reports of
the Cavendish Laboratory in Cambridge and the corresponding material from
King's College London, plus the material at Caltech and the correspondence
e.g between Linus Pauling and James Watson, are primary. Indeed, the
historian typically works (does he or she not?) with "literature" which at
the time of production was regarded as gray in one sense or another.

If I have not fallen off my limb, then it follows that our situation with
regards to research in computing is the same. Take the case of hypertext
research. Those who are building systems tend to publish non-commercially
in the form of conference papers, which can be frustratingly difficult to
get to if you don't go to the right conferences and your institution does
not pay for the rights of access to the contents of www.acm.org/dl. Even if
your institution does, the huge amount of stuff you need to plough through
shows quickly that the attitude of the authors tends to be very different
from those in the humanities who write for publication. It's gray
literature one finds -- gray to the authors because, I am guessing, it's
quite secondary as far as they are concerned to the real work, which is
manifested in the building of systems. But from the perspective of
humanities computing, as to the historian, this literature is primary.

So, I conclude, this topic is very important to us. And I salute Manfred
Thaller's wit in calling the series he published at the Max Planck Institut
fuer Geschichte (Goettingen) the "Halbgraue Reihe zur historischen
Fachinformatik", the "Half-Gray Series on Historical Information
Technology" http://www.geschichte.mpg.de/deutsch/hgr.html.